Brain-Type Natriuretic Peptide in the Diagnosis and Management of Persistent Pulmonary Hypertension of the Newborn: In Reply

Abstract

In Reply.—I thank Baptista et al for their interest in my research. In the article, my co-workers and I1 hypothesized that brain-type natriuretic peptide (BNP) levels would be elevated in any pathologic condition that resulted in abnormal stress on the ventricles. This would be true of some, but not all, forms of congenital heart disease. It seems from the preliminary data that the doctors are on their way to confirming that hypothesis.We excluded infants with congenital heart disease from our study because of potential limitations of using the BNP assay in this setting that occurred to us while planning for this project. First, BNP is a marker for ventricular stress. It is not specific to any particular disease state. Although BNP is elevated in infants with persistent pulmonary hypertension (PPHN), it can also be expected to be elevated in any infant with congenital heart disease that results in a state of ventricular stress. Second, low levels of BNP, while suggestive of no ventricular stress, do not rule out serious (potentially life-threatening) cardiac or respiratory diseases.As we concluded in the article, “the results of this study should not be interpreted as showing that BNP levels are diagnostic of PPHN or that measuring BNP levels can be used in place of echocardiography.” It is unfortunate that not all practicing pediatricians or neonatologists have access to 24-hour/7-day-a-week echocardiography services. Serum BNP level is a useful adjuvant diagnostic tool that can be used in conjunction with a thorough physical examination, blood gas analysis, and other information to help physicians determine the proper treatment for the patient. Again, we emphasize that “[p]hysicians should have increased suspicion of PPHN, or other states of ventricular stress, when caring for a term or near-term newborn with RD [respiratory distress] and an elevated BNP level.”We feel that any infant with respiratory distress and an elevated BNP level should receive a thorough evaluation, likely including echocardiography, to determine the proper course of treatment. We are glad that preliminary data from Baptista et al support our hypothesis and that they agree with the conclusions we put forth in our article. We look forward to their final manuscript.